docs: def plot_neuron3d(ax, nrn, neurite_type=NeuriteType.all,
                    diameter_scale=_DIAMETER_SCALE, linewidth=_LINEWIDTH,
                    color=None, alpha=_ALPHA):
      '''
      Generates a figure of the neuron,
      that contains a soma and a list of trees.
  
      Args:
          ax(matplotlib axes): on what to plot
          nrn(neuron): neuron to be plotted
          neurite_type(NeuriteType): an optional filter on the neurite type
          diameter_scale(float): Scale factor multiplied with segment diameters before plotting
          linewidth(float): all segments are plotted with this width, but only if diameter_scale=None
          color(str or None): Color of plotted values, None corresponds to default choice
          alpha(float): Transparency of plotted values
      '''
      plot_soma3d(ax, nrn.soma, color=color, alpha=alpha)
  
      for neurite in iter_neurites(nrn, filt=tree_type_checker(neurite_type)):
          plot_tree3d(ax, neurite,
                      diameter_scale=diameter_scale, linewidth=linewidth,
                      color=color, alpha=alpha)
  
      ax.set_title(nrn.name)